In a June 3 letter, several trade associations representing corporate defined benefit plans asked the PBGC's board of directors to intervene and drastically curtail the PBGC's authority in cases where companies experience major operational change.

PBGC officials are expected to release their guidance sometime this summer.

At issue is Section 4062(e) of the Employee Retirement Income Security Act. That section allows the agency to step in if 20% or more of employees covered by a defined benefit plan will lose their jobs in the event of an operational shutdown or other major event at a facility. In those cases, the PBGC calculates pension liabilities that companies must either put into their pension plans as if the plans were being terminated or provide financial guarantees to cover.

Some members of Congress also are hearing plenty of complaints, and have introduced legislation that would halt the Section 4062(e) enforcement program, at least temporarily.

“The business community has expressed some very legitimate concerns, and it is not clear to me that participants are seeing any real benefit from the program,” said Sen. Tom Harkin, D-Iowa, chairman of the Senate Health, Education, Labor and Pensions Committee, in an e-mail sent in response to a request for comment. “I am concerned that PBGC's 4062(e) enforcement program is doing more harm than good” by upsetting sponsors of defined benefit plans.

Legislation Sen. Harkin introduced earlier this year to create a universal retirement plan also calls for a two-year moratorium on 4062(e) enforcement while the Government Accountability Office studies its impact.

Rep. Richard Neal, D-Mass., has introduced legislation that would clarify retroactively for all open cases that only an actual facility shutdown could trigger an event.

When PBGC officials first devised the liability formula in 2007, enforcement was aggressive. But under a pilot program launched in late 2012, the agency gives a pass to cases involving small plans or financially sound corporate parents, which agency officials say removes 92% of plans from scrutiny. To prove its good intentions, the agency last year suspended 4062(e) negotiations with 17 companies where it initially sought $450 million in financial guarantees, including Anheuser-Busch InBev North America, St. Louis; Whirlpool Corp., Benton Harbor, Mich.; and Procter & Gamble Co., Cincinnati.

Agency officials also reviewed settlements reached between 2007 and 2010 that added up to $1.7 billion in pension funding demands, and took plan sponsors off the hook for $1 billion of that, after criticism increased.

“It is our job to look, but we are not applying it in the majority of cases,” said PBGC Director Joshua Gotbaum in an interview last week. “Since 2013, there have been thousands of transactions, but only 13 cases where we demanded a settlement. In 52 cases, we decided there was no risk.” Of those 13 settlements, 11 required sponsors to put a collective $160 million into their plans, while the other two settlements asked for financial guarantees.

“We have gotten smarter about how and when we use that authority,” said Mr. Gotbaum, “but it is virtually the only tool that PBGC has to protect workers' pensions before a plan is terminated.”

Mr. Gotbaum said he will continue to engage with company executives, labor representatives and pension plan advocates and is hopeful the new guidance the agency plans to publish this summer will better explain how the enforcement policy is implemented.

In their letter, associations including the American Benefits Council and the Committee on Investment of Employee Benefit Assets complained about “inconsistent” enforcement that is “adversely affecting critical business transactions.” The letter was delivered to PBGC board members — Labor Secretary Thomas Perez, Commerce Secretary Penny Pritzker and Treasury Secretary Jacob Lew — by Constance Donovan, the PBGC's participant and plan sponsor advocate.

Ms. Donovan started work in the new post in December. From her first week on the job, she heard from sponsors and their Washington representatives about Section 4062(e). She has been asked to advocate on behalf of three companies facing substantial 4062(e) liabilities, whom she declined to identify. Ms. Donovan said she expects the board will take the issue seriously.

For some plan sponsors, the complaint is that PBGC's calculated liabilities far exceed the business transactions involved. Instead of regular funding formulas for ongoing plans, the agency uses the more conservative plan termination basis, taking the percentage of plan participants who lose their jobs in the transaction, and multiplying it by the plan's level of underfunding. Although a small number of employees are affected, sponsors already funding their pension plans will have to put aside millions of dollars more. “It can be a shock, particularly when the downsizing event has had an immaterial or even a positive impact on the company and thus on the financial soundness of the plan,” said Harold Ashner, a former PBGC assistant general counsel for legislation and regulations, now a partner at law firm Keightley & Ashner LLP, Washington, which represents corporations in 4062(e) cases.

His clients are bracing for an even bigger shock as they see the PBGC flexing its authority in recent months to file liens on corporate assets to get settlement agreements. Just the threat of filing liens “may have a significant adverse impact on the business,” said Mr. Ashner.

Even financially strong companies have to worry about the contingency of 4062(e) enforcement action “with every transaction they do,” said Kent Mason, an attorney at law firm Davis & Harman LLP, who is outside counsel for the American Benefits Council in Washington. “If the company goes through a down cycle, they could have $50 million or $100 million of liability attributable to small transactions.”